Per CNET, from now through August 20, RadioShack is cutting US$30 off the price of Apple’s iPhone 4, as well as the iPhone 3GS. Deeper discounts can be had if buyers bring in their iPhone 3G or iPhone 3GS and use the company’s Trade and Save program, which it’s had going since before the iPhone 4 went on sale.

RadioShack and Target unofficially lowered pricing on phones at the end of last month, with those prices going into effect on July 31. Today’s news puts an endmark on the deal, as well as adding the capability to stack those savings with the company’s trade-in service.

Apple is expected to bring out a next-generation iPhone between now and October, with recent rumors citing the company’s launch window for October, though a slew of reports from earlier this year said it would be sometime next month.

Stay tuned for additional details as they become available and, hey, savings are never a bad thing.